I have no idea about the characteristics of the OEM or your MAF, but the hotwire MAF:s used by Ford are highly non-linear. They output a voltage proportional to the airflow, but the non-linearity of them makes it somewhat hard to replace the OEM MAF:s unless you have the ability to reprogram the ECU.
Some are replacing the single Ford MAF with dual MAF:s and tries to use an averaging circuit to provide a the ECU with a proper signal. This is theoretically a problem as flowing twice the amount of air through one MAF does not provide twice the signal, so the proper way is to convert each of the signals into a signal that is linearly proportional to the airflow, which then can be averaged and fed to the ECU, which then needs to have a linear table for converting voltage into airflow.
Going from dual MAF:s into a single is probably easier as you would then only have to wire the single output from the MAF to both inputs to the ECU and then adjust the table(s) in the ECU accordingly. Requires reprogramming the ECU though to work properly.